Add support to python 3.11

[thinkall]

Why are these changes needed?

Verify and add support to python 3.11

Related issue number

Closes #1079

Checks

• I've included any doc changes needed for https://microsoft.github.io/FLAML/. See https://microsoft.github.io/FLAML/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[thinkall]

Issues:

ERROR: Cannot install FLAML, flaml[test]==2.0.0rc2 and transformers[torch]==4.26.0 because these package versions have conflicting dependencies.

The conflict is caused by:
    flaml[test] 2.0.0rc2 depends on torch; extra == "test"
    transformers[torch] 4.26.0 depends on torch!=1.12.0 and >=1.7; extra == "torch"
    pytorch-forecasting 0.10.1 depends on torch<2.0 and >=1.7
ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts
    flaml[test] 2.0.0rc2 depends on torch; extra == "test"
    transformers[torch] 4.26.0 depends on torch!=1.12.0 and >=1.7; extra == "torch"
    pytorch-forecasting 0.10.0 depends on torch<2.0 and >=1.7
    flaml[test] 2.0.0rc2 depends on torch; extra == "test"
    transformers[torch] 4.26.0 depends on torch!=1.12.0 and >=1.7; extra == "torch"
    pytorch-forecasting 0.9.2 depends on torch<2.0 and >=1.7
    flaml[test] 2.0.0rc2 depends on torch; extra == "test"
    transformers[torch] 4.26.0 depends on torch!=1.12.0 and >=1.7; extra == "torch"
    pytorch-forecasting 0.9.1 depends on torch<2.0 and >=1.7
    flaml[test] 2.0.0rc2 depends on torch; extra == "test"
    transformers[torch] 4.26.0 depends on torch!=1.12.0 and >=1.7; extra == "torch"
    pytorch-forecasting 0.9.0 depends on torch<2.0 and >=1.7

To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict

[thinkall]

https://github.com/microsoft/FLAML/actions/runs/5266667650/jobs/9520899434?pr=1080